Due to the increase of the deformity of ankle joints by aging and diversification of foot wear, it is necessary to elucidate the influence of long-term load on the ankle joints. However, such studies have not been performed. We investigated how various standing postures exert the pressure on the three-dimensional ankle joints. The ankle joints were assumed to undergo a uniform distribution load and two kinds of triangular load. First, the growth criterion parameters of the strain energy density were determined by applying the finite element method to each 3D model of the normal ankle joints using the growth-strain method. Then, growth analysis of these models was performed using the previously obtained growth criterion parameters of the strain energy density. Finally, strain energy distributions and configuration changes of the ankle joints were illustrated and were compared. As a result, equalization of the stress and optimization of the shape were performed. However, in the case of all load conditions, most of the shape transformation of the ankle joints usually did not occur. Therefore, it was clarified that the various assumed standing posture had little affected on the deformity of the ankle joints.

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Methods and results of in vitro experiments examining the electromagnetic interference (EMI) imposed on active implantable medical devices (AIMDs) by electronic article surveillance (EAS) systems are presented. Examined EAS systems include eleven models provided by four manufacturers. They are classified into four categories according to operating principle, and consist of one magnetic-type system, four acousto-magnetic type systems, five electromagnetic-type systems, and one microwave-type system. Examined AIMDs include five models of implantable cardiac pacemakers and five models of implantable cardioverter defibrillators (ICDs) provided by six manufacturers. These EAS systems and AIMDs are currently available in the Japanese market. The in vitro test system is based upon Irnich's flat torso phantom. The observed EMI on pacemakers is either missing pulses or undesirable generation of asynchronous pulses. The observed EMI on ICDs are inappropriate tachyarrhythmia detection and erroneous delivery of therapy. To summarize the results, in the worst case for pacemakers, interference occurred when approaching the EAS system up to 90 cm and entering the gate of the EAS system. The most significant effect was complete omission of pacing pulse and continuous generation of asynchronous pulses. These were observed when the pacemaker was set at maximum sensitivity. In the worst case for ICDs, interference occurred when approaching the EAS pedestal up to 90 cm within the gate. The most significant effect was inappropriate or inhibited tachyarrhythmia detection at 60 cm. These effects were drastically suppressed when the sensitivity was reduced and when the AIMD was far from the EAS system and magnetic field was attenuated. All AIMDs that experienced EMI returned to normal operation mode upon departing the EAS system.

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Pulse oximetry is used world wide in medical practice. Development of theory of pulse oximetry is still necessary for improving its performance. First we hypothesized a completely scattered light field in the object, and adopted Sir Arthur Schuster's scattering theory as the basis of theory of pulse oximetry. Second, a theoretical formula for pulse oximetry was proposed considering the arterial blood and tissue. Third, with a volunteer experiment the theoretical formula was proved and some constants were obtained.

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